This tetraploid (2n = 24) perennial is widespread across eastern and central states. P. rugelii is often abundant in the same kind of mowed or trampled sunny moist fertile sites as major, and these two species are often mixed in northern regions. However, major is generally absent from more mesic shady trailsides, where rugelii can be quite common. B noted that var. asperula Farw. can often be distinguished but that intermediates occur; that variety is not recognized in recent treatments. In the central Bluegrass region of Ky., spikes of robust plants are sometimes up to 5-6.5 (7) dm tall, far surpassing the generally reported height of 1-3.5 dm; yet leaf blades on such plants are no larger than reported elsewhere, up to ca. 30 x 15 cm (Y).